【英语时差8,16】鸟类迁徙与消化系统2

 However, when birds migrate, they can’t afford to spend all that energy on digestion¹. And so their digestive system partially² shuts down and stops renewing itself, so all that energy can be diverted into fueling flight. In other words, migrating birds end up using their own body tissues as fuel. Then, when they arrive at their destination, the birds eat foods that are high in protein so that their digestive system can rebuild itself and return to normal, which usually takes a few days. This need for protein-rich food is something ornithologists didn’t always know about. Given that less than half of the birds that leave don’t make it back, the more scientists know about the stresses of migration³, the better.

1 digestion   

n.消化，吸收

参考例句：

• This kind of tea acts as an aid to digestion.这种茶可助消化。
• This food is easy of digestion.这食物容易消化。

2 partially   

adv.部分地，从某些方面讲

参考例句：

• The door was partially concealed by the drapes.门有一部分被门帘遮住了。
• The police managed to restore calm and the curfew was partially lifted.警方设法恢复了平静，宵禁部分解除。

3 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。